• Journal of Energy Engineering
• /
• v.25 no.4
• /
• pp.251-258
• /
• 2016

This article reports current status of micro fuel cell-combined heat and power (${\mu}FC$-CHP) systems which utilize both power and heat generated by fuel cells. There are several options for constructing CHP systems and among them, fuel cells are the most useful and their total energy efficiency combining heat and power can reach up to about 90%. Fuel cells are classified as five types based on the electrolyte, but the most suitable fuel cell types for the ${\mu}FC$-CHP system are proton exchange membrane fuel cells (PEMFCs) and solid oxide fuel cells (SOFCs). ${\mu}FC$-CHP systems have several advantages such as decrease of the transmission-distribution loss, reduced costs of electricity due to distributed power generation, and environmental-friendliness owing to zero emission. The main drawback of the ${\mu}FC$-CHP systems is the high initial investment, however, it keeps decreasing as the technology development reduces production costs. Currently, Japan is the most leading country of the ${\mu}FC$-CHP market, however, Korea tries to expand the market by planning the deployment of 1 million units of ${\mu}FC$-CHP systems and governmental subsidiary supporting of half of the install price. In this report, integration technologies for connecting FC and CHP, and technology trends of leading countries are presented as well.

• Korean Journal of Soil Science and Fertilizer
• /
• v.37 no.4
• /
• pp.266-287
• /
• 2004

The non infecting, plant associated bacteria have attracted increased attention for stimulating plant growth and as environmental friendly plant protecting agents. Pink-pigmented facultatively methylotrophic bacteria (PPFMs), classified as Methylobacterium spp., are persistent colonizers of plant leaf surfaces. As the leaves of most or all plants harbor PPFMs that utilize leaf methanol as their sole source of carbon and energy, which is a specific attribute of the genus Methylobacterium. Although they are not well known, these bacteria are co-evolved, interacting partners in plant metabolism. This claim is supported, for example, by the following observations: (1) PPFMs are seed-transmitted, (2) PPFMs are frequently found in putatively axenic cell cultures, (3) Low numbers of seed-borne PPFMs correlate with low germinability, (4) Plants with reduced numbers of PPFM show elevated shoot/root ratios, (5) Foliar application of PPFMs to soybean during pod fill enhances seed set and yield, (6) Liverwort tissue in culture requires PPFM-produced vitamin B12 for growth, (7) treated plants to suppress or decrease disease incidence of sheath blight caused by Rhizoctonia solani in rice, and (8) the PPFM inoculation induced number of stomata, chlorophyll concentration and malic acid content, they led to increased photosynthetic activity. Methylobacterium spp. are bacterial symbionts of plants, shown previously to participate in plant metabolism by consuming plant waste products and producing metabolites useful to the plant. There are reports that inform about the beneficial interactions between this group of bacteria and plants. Screening of such kind of bacteria having immense plant growth promoting activities like nitrogen fixation, phytohormone production, alleviating water stress to the plants can be successfully isolated and characterized and integration of such kind of organism in crop production will lead to increased productivity.

• Journal of the Economic Geographical Society of Korea
• /
• v.4 no.2
• /
• pp.79-96
• /
• 2001

This paper introduces a new type of industrial cluster developed at the CBD of Seoul. Conventionally, clusters are said to be consisted of hi-tech, often If activities, manufacturing industries or artisan craft industries with increasing vertical integration and performance usually supported by venture capitals and favorable business infrastructure, not to mention governments', be it central or local, incentive plans. The study area, Cheonggyechon region has long been a traditional CBD frame of Seoul, Korea, being troubled by deterioration, traffic jams, and environmental degradation as most inner cities experience. Recently. this region has transformed to the most dynamic and productive area not by IT industries but by apparel and fashion activities. The study of the developmental trajectory and key characteristics for this kind of industrial cluster can give us insight both for the transition of inner city and for the cluster theory. This Paper firstly briefly Profiles the growth of the Cheonggyechon region over the past decade. It then shows the current spatial and business structure of the new industrial cluster, focusing on the fact that transactions costs are reduced, the creation and flow of information improves. and the local institutions are prone to be most responsive to the new cluster's specialized needs. The third section presents the key components of the customized production-distribution-shopping cluster development process, emphasizing the localized networking. social capital, spontaneous institutionalization of associational economic climate, and cultural economy based on place-specific inertia. The paper concludes with some comments about the prospects and perils of the new industrial cluster of Seoul.

• Composites Research
• /
• v.13 no.5
• /
• pp.50-59
• /
• 2000

In this paper, two methods to suppress flutter of the composite panel are examined. First, in the active control method, a controller based on the linear optimal control theory is designed and control input voltage is applied on the actuators and a PZT is used as actuator. Second, a new technique, passive suppression scheme, is suggested for suppression of the nonlinear panel flutter. In the passive suppression scheme, a shunt circuit which consists of inductor-resistor is used to increase damping of the system and as a result the flutter can be attenuated. A passive damping technology, which is believed to be more robust suppression system in practical operation, requires very little or no electrical power and additional apparatuses such as sensor system and controller are not needed. To achieve the great actuating force/damping effect, the optimal shape and location of the actuators are determined by using genetic algorithms. The governing equations are derived by using extended Hamilton's principle. They are based on the nonlinear von Karman strain-displacement relationship for the panel structure and quasi-steady first-order piston theory for the supersonic airflow. The discretized finite element equations are obtained by using 4-node conforming plate element. A modal reduction is performed to the finite element equations in order to suppress the panel flutter effectively and nonlinear-coupled modal equations are obtained. Numerical suppression results, which are based on the reduced nonlinear modal equations, are presented in time domain by using Newmark nonlinear time integration method.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.12
• /
• pp.614-621
• /
• 2019

A generalized laminated composite beam element is presented for the flexural and buckling analysis of laminated composite beams with double and single symmetric cross-sections. Based on shear-deformable beam theory, the present beam model accounts for transverse shear and warping deformations, as well as all coupling terms caused by material anisotropy. The plane stress and plane strain assumptions were used along with the cross-sectional stiffness coefficients obtained from the analytical technique for different cross-sections. Two types of one-dimensional beam elements with seven degrees-of-freedom per node, including warping deformation, i.e., three-node and four-node elements, are proposed to predict the flexural behavior of symmetric or anti-symmetric laminated beams. To alleviate the shear-locking problem, a reduced integration scheme was employed in this study. The buckling load of laminated composite beams under axial compression was then calculated using the derived geometric block stiffness. To demonstrate the accuracy and efficiency of the proposed beam elements, the results based on three-node beam element were compared with those of other researchers and ABAQUS finite elements. The effects of coupling and shear deformation, support conditions, load forms, span-to-height ratio, lamination architecture on the flexural response, and buckling load of composite beams were investigated. The convergence of two different beam elements was also performed.

• Journal of Environmental Impact Assessment
• /
• v.25 no.4
• /
• pp.261-279
• /
• 2016

Trends of food and energy consumptions in South Korea, North Korea, and the Korean Peninsula were shown and consumptions of food and energy for the integrated Korean Peninsula with several Cases were predicted, and the directions for the environmental resources management were suggested in this study. The Food Supply Quantity, the Protein Supply Quantity, and the Food Supply of North Korea were less than those of South Korea, the Eastern Asia, and World after 1990s. However, it is expected that the food consumption in North Korea will increase, if two Koreas are integrated. If the Food Supply Quantity of North Korea is the same as that of South Korea with the maximum projected population of integrated two Koreas by 2055, the food consumption in the Korean Peninsula would increase by 25% compared with the 2011 food consumption of integrated two Koreas. Thus, the choice of diet should be carefully considered and the increase of agricultural productivity is required. Energy consumption in North Korea is very small comparing to that of South Korea and fraction of coal in energy usage of North Korea is very high. If the energy consumption per capita of North Korea after integration be the same as that of South Korea in 2011, the energy consumption in the Korean Peninsula would increase by 45% compared with the 2011 energy consumption of integrated two Koreas. To minimize the environmental effects caused by energy consumption, the energy plan with the reduced fraction of coal in energy supply of North Korea should be adopted and advanced technology with higher efficiency should be applied to establish or expand the energy facility in North Korea.

• Journal of Plant Biotechnology
• /
• v.37 no.1
• /
• pp.102-109
• /
• 2010

Fructan has been found to accumulate in various tissues during periods when light levels increased carbon fixation where low temperatures reduced growth rates while photosynthesis continued. In this study, we have cloned 1-sucrose:sucrose fructosyl transferase(1-sst) and 1-fructan: fructan fructosyl transferase (1-fft, a key enzyme for the synthesis of fuctan) from Jerusalem Artichoke (Helianthus tuberosus L.). The recombinant vector with 1-sst and 1-fft has been constructed under the control of 35S promoter of KJGV-B2 vector and transgenic plants obtained by Agrobacterium tumefaciens LBA4404. PCR analysis carried out on the putative transgenic plants for amplification of the coding region of specific gene (1-sst, 1-fft), and HPT genes. Transgenic lines carrying of 1-sst and 1-fft were confirmed for integration into the rice genome using Southern blot hybridization and RT-PCR. The transgenic plants in $T_2$ generation were selected and expression pattern analysis revealed that 1-sst and 1-fft were stable. This analysis confirmed the presence of low-molecular-weight fructan in the seedling of the transgenic rices. Therefore, cold tolerance and carbohydrate metabolism will be possible to develop resistant plants using the transgenic rice.

• Korean Journal of Animal Reproduction
• /
• v.27 no.2
• /
• pp.179-185
• /
• 2003

To determine whether the diphtheria toxin-A (DT) gene disrupts development of thymocytes in transgenic animal, the DT-A gene was used for the production of transgenic mice directed by proximal Ick promoter sequences. Two transgenic founder mice that contained several copies of transgene were produced by DNA microinjection and integration of transgene in transgenic mice was confirmed by PCR and Southern blotting analysis. Transgenic $F_1$ and $F_2$ mice were produced by outbreeding of founder and $F_1$ mice to investigate expression of transgene and phenotypes in transgneic mice. Expression of the diphtheria toxin gene was confirmed in thymus, spleen and liver of transgenic mice by RT-PCR. In circulating blood of transgenic mice, lower number of circulating white blood cells and platelets were observed compared with that of normal mice. In addition, transgneic mice had reduced number of circulating peripheral T-cells analyzed by FACS with anti-CD3 antibody. The data in these transgenic mice indicate that DT gene can play a disruptive role in developing thymocytes of transgenic mice resulted in lower number of T-cells that can be applicable to a wide range of tissues in other animals.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.31 no.2
• /
• pp.87-95
• /
• 2018

This paper introduces a new explicit spectral element method for the simulation of SH-waves in semi-infinite domains. To simulate the wave motion in unbounded domains, it is necessary to reduce the infinite extent to a finite computational domain of interest. To prevent the wave reflection from the trunctated boundaries, perfectly matched layer(PML) wave-absorbing boundary is introduced. The forward problem for simulating SH-waves in PML-truncated domains can be formulated as second-order PDEs. The second-order semi-discrete form of the governing PDEs is constructed by using a mixed spectral elements with Legendre-gauss-Lobatto quadrature method, which results in a diagonalized mass matrix. Then the second-order semi-discrete form is transformed to a first-order, whose solutions are calculated by the fourth-order Runge-Kutta method. Numerical examples showed that solutions of SH-wave in the two-dimensional analysis domain resulted in stable and accurate, and reflections from truncated boundaries could be reduced by using PML boundaries. Elastic wave propagation analysis using explicit time integration method may be apt for solving larger domain problems such as three-dimensional elastic wave problem more efficiently.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2010.10a
• /
• pp.14-14
• /
• 2010

Vitamin C (ascorbic acid) is an essential component for collagen biosynthesis and also for the proper functioning of the cardiovascular system in humans. Unlike most of the animals, humans lack the ability to synthesize ascorbic acid on their own due to a mutation in the gene encoding the last enzyme of ascorbate biosynthesis. As a result, vitamin C must be obtained from dietary sources like plants. In this study, we have developed two different kinds of transgenic potato plants (Solanumtuberosum L. cv. Taedong Valley) overexpressing strawberry GalUR and mouse GLoase gene under the control of CaMV 35S promoter with increased ascorbic acid levels. Integration of the these genes in the plant genome was confirmed by PCR and Southern blotting. Ascorbic acid(AsA) levels in transgenic tubers were determined by high-performance liquid chromatography(HPLC). The over-expression of these genes resulted in 2-4 folds increase in AsA intransgenic potato and the levels of AsA were positively correlated with increased geneactivity. The transgenic lines with enhanced vitamin C content showed enhanced tolerance to abiotic stresses induced by methyl viologen(MV), NaCl or mannitol as compared to untransformed control plants. The leaf disc senescence assay showed better tolerance in transgenic lines by retaining higher chlorophyll as compared to the untransformed control plants. Present study demonstrated that the over-expression of these gene enhanced the level of AsA in potato tubers and these transgenics performed better under different abiotic stresses as compared to untransformed control. We have also investigated the mechanism of the abiotic stress tolerance upon enhancing the level of the ascorbate in transgenic potato. The transgenic potato plants overexpressing GalUR gene with enhanced accumulation of ascorbate were investigated to analyze the antioxidants activity of enzymes involved in the ascorbate-glutathione cycle and their tolerance mechanism against different abiotic stresses under invitro conditions. Transformed potato tubers subjected to various abiotic stresses induced by methyl viologen, sodium chloride and zinc chloride showed significant increase in the activities of superoxide dismutase(SOD, EC 1.15.1.1), catalase, enzymes of ascorbate-glutathione cycle enzymes such as ascorbate peroxidase(APX, EC 1.11.1.11), dehydroascorbate reductase(DHAR, EC 1.8.5.1), and glutathione reductase(GR, EC 1.8.1.7) as well as the levels of ascorbate, GSH and proline when compared to the untransformed tubers. The increased enzyme activities correlated with their mRNA transcript accumulation in the stressed transgenic tubers. Pronounced differences in redox status were also observed in stressed transgenic potato tubers that showed more tolerance to abiotic stresses when compared to untransformed tubers. From the present study, it is evident that improved to lerance against abiotic stresses in transgenic tubers is due to the increased activity of enzymes involved in the antioxidant system together with enhanced ascorbate accumulated in transformed tubers when compared to untransformed tubers. At moment we also investigating the role of enhanced reduced glutathione level for the maintenance of the methylglyoxal level as it is evident that methylglyoxal is a potent cytotoxic compound produced under the abiotic stress and the maintenance of the methylglyoxal level is important to survive the plant under stress conditions.